Browsing by Author "Tamer A.U."

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    Antibacterial activity of some actinomycetes isolated from farming soils of Turkey
    (Academic Journals, 2004) Oskay M.; Tamer A.U.; Azeri C.
    A total of 50 different actinomycete strains were recovered from farming soil samples collected from Manisa Province and its surrounding. These were then assessed for their antibacterial activity against four phytopathogenic and six pathogenic bacteria. Results indicated that 34% of all isolates are active against, at least, one of the test organisms; Agrobacterium tumefaciens, Erwinia amylovora, Pseudomonas viridiflova, Clavibacter michiganensis subsp. michiganensis, Bacillus subtilis ATTC 6633, Klebsiella pneumoniae ATTC 10031, Enterococcus feacalis ATCC 10541, Staphylococcus aureus ATCC 6538, Esherichia coli ATCC 29998 and Sarcina lutea ATCC 9341. According to antibacterial activity and spectrum broadness, seven of the isolates were selected and characterized by conventional methods. The unusual antibiotic profile of these isolates underlined their potential as a source of novel antibiotics. © 2004 Academic Journals.
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    Antimicrobial and antioxidant activities of mycelia of 10 wild mushroom species.
    (2010) Kalyoncu F.; Oskay M.; Saǧlam H.; Erdoǧan T.F.; Tamer A.U.
    Antimicrobial and antioxidant activities of mycelia obtained from 10 wild edible mushrooms-Armillaria mellea, Meripilus giganteus, Morchella costata, Morchella elata, Morchella esculenta var. vulgaris, Morchella hortensis, Morchella rotunda, Paxillus involutus, Pleurotus eryngii, and Pleurotus ostreatus-were investigated. For determination of antimicrobial activities of these mushrooms, ethanol extracts were examined with 11 test microorganisms by the agar well diffusion method. P. ostreatus and M. giganteus were the most active species against both bacteria and yeast. Antioxidant properties of ethanol extracts were studied by the 1,1-diphenyl-2-picrylhydrazyl free radical scavenging method. Among the mushroom extracts, M. elata showed the most potent radical scavenging activity. This research has shown that these 10 wild macrofungi have potential as natural antioxidants and antibiotics.
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    Thermoactive cellulase-free xylanase production from alkaliphilic Bacillus strains using various agro-residues and their potential in biobleaching of kraft pulp
    (2010) Azeri C.; Tamer A.U.; Oskay M.
    The four bacterial strains were isolated on media containing xylan and screened for xylanase activity. The bacterial strains (Ag12, Ag13, Ag20 and Ag32) were characterized based on morphological, biochemical and physiological characters and identified as belonging to the genus Bacillus. The effects of different factors such as pH (7.0 - 10.0), temperature (25.0 - 50.0 °C) and inexpensive agro-residues (wheat straw, wheat bran and corncob) on xylanase production of strains were studied under shake flask conditions. Maximal enzyme activities were obtained by cultivation in birch-wood xylan, but high enzyme production was also obtained on wheat straw and corncob when cultivated at pH 8.5. Under optimized fermentation conditions, no cellulolytic activity were detected on the crude extracts. The effects of temperature (40.0 - 80.0 °C), pH (6.0 - 10.0) and salt concentration (1.0, 5.0 and 10.0%) on the xylanases activity were determined. The maximum activity was obtained temperature 60.0 °C and pH at 9.0. The enzyme was stable at 60.0 °C for more than 60 min, suggesting that the xylanases of Bacillus strains are thermoactive and being of interests for biobleaching processes. The effectiveness of crude xylanases from the strains Ag12, Ag20 and Ag32 on kraft pulp were carried out at pH 9.0 at 60.0 °C. Biobleaching studies of kraft pulp with xylanases and its subsequent treatment with 1.0% EDTA (30 min at 50.0 °C) and peroxide (80 min at 70.0 °C), showed that the enzymes reduced the kappa number by 27.4, 61.7 and 75.3% and enhanced the brightness by 1.0, 1.5 and 3.0% from xylanases produced by strains Ag12, Ag20 and Ag32, respectively. These results suggest that the application of this xylanases to the paper and pulp industry may be very promising. © 2010 Academic Journals.
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    Isolation and screening for antimicrobial activities of culturable mesophilic streptomyces strains from north cyprus soils
    (2010) Oskay M.; Tamer A.U.; Karaboz I.
    A total of 249 different Streptomyces strains were isolated from different sites of the North Cyprus habitats for their antimicrobial potential. Out of these, 66 isolates exhibited inhibitory activity against at least one of the tested microorganisms. Approximately, 51% isolates produced antibacterial substances against Gram-positive bacteria, 6% against Gram-negative bacteria, and 23% against both Gramnegative and Gram-positive bacteria, whereas 18% of isolates showed antifungal activity. According to the spectrum of broadness, the two most active isolates were selected, and designed as KGG13 and KVK11. A great variety of morphological, physiological and biochemical features of selected strains were determined for their taxonomie position, and obtained data strongly suggested that these strains belong to the genus Streptomyces, confirmed by their antimicrobial activity in batch culture. In order to standardize the antibiotic production, some cultural conditions, such as the effect of different temperatures, nature of carbon sources, pH value, and time incubation in h, were determined. The highest antimicrobial activities were obtained when glucose and glycerol at 1% (w/v) was used as sole carbon source, at pHs 7.3 and 7.5 for the strains KGG13 and KVK11, respectively. © by PSP.
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    Pandoraea oxalativorans sp. nov., Pandoraea faecigallinarum sp. nov. and Pandoraea vervacti sp. nov., isolated from oxalate-enriched culture
    (2011) Sahin N.; Tani A.; Kotan R.; Sedláček I.; Kimbara K.; Tamer A.U.
    Five isolates, designated TA2, TA4, TA25 T KOx T and NS15 T were isolated in previous studies by enrichment in mineral medium with potassium oxalate as the sole carbon source and were characterized using a polyphasic approach. The isolates were Gram-reaction-negative, aerobic, non-spore-forming rods. Phylogenetic analyses based on 16S rRNA and DNA gyrase B subunit (gyrB) gene sequences confirmed that the isolates belonged to the genus Pandoraea and were most closely related to Pandoraea sputorum and Pandoraea pnomenusa (97.2-99.7% 16S rRNA gene sequence similarity). The isolates could be differentiated from their closest relatives on the basis of several phenotypic characteristics. The major cellular fatty acid profiles of the isolates comprised C 16: 0, C 18: 1 ω 7c, C17: 0 cyclo and summed feature 3 (C 16: 1ω7c and/or iso-C15: 0 2-OH). On the basis of DNA-DNA hybridization studies and phylogenetic analyses, the isolates represent three novel species within the genus Pandoraea, for which the names Pandoraea oxalativorans sp. nov. (TA25 T 5NBRC 106091 T 5CCM 7677 T 5DSM 23570 T), Pandoraea faecigallinarum sp. nov. (KOx T 5NBRC 106092 T 5CCM 2766 T 5DSM 23572 T) and Pandoraea vervacti sp. nov. (NS15 T 5NBRC 106088 T 5CCM 7667 T 5DSM 23571) are proposed. © 2011 IUMS.